1. Field of the Invention
This invention relates generally to a lifting device and more particularly to a lift-assist apparatus having a pneumatic motor which is defined by a substantially stationary piston and a slidable cylinder, wherein the piston further includes a pressure chamber. A carriage-lift framework operably engages the cylinder by means of a cam device.
2. General Description of the Prior Art
It is well recognized in the art that various problems and difficulties have been encountered in lifting heavy articles out of as well as inserting them into very confined areas, especially with respect to trunks and storage wells of passenger cars. These problems exist with all types of passenger vehicles.
Such deep trunk areas have greater capacity for carrying such items as luggage, hardware, typewriters, copier machines, golf clubs, etc., yet in providing such storage space a problem has been created in that it becomes very difficult to remove these same articles stored therein.
Due to many design changes in recent years, motor vehicles tend to be smaller overall and thus difficulties in access to deep-well storage spaces have become very prevalent. To the applicants' knowledge, an apparatus as herein described and claimed has not been available for use in conjunction with passenger vehicles. It should be noted, however, that the present invention is not limited to passenger vehicles but may also be employed in various other fields where there are similar access problems.
Several lift mechanisms have been provided for vehicles but, generally, such devices have been limited to use in truck and/or other larger vehicles. These known devices also have features that restrict their use, and they are complicated and expensive, but first and foremost they are not suitable or compatible for use with present-day passenger vehicles.
As examples of prior-art devices, one may refer to the following United States patents:
U.S. Pat. No. 1,546,698 to L. Zoll et al defines a folding or extension scaffold, and U.S. Pat. No. 2,626,179 to F. C. Gonzalez discloses a convertible truck and trunk compartment for automobiles, which provided a trunk compartment having foldable sides and a foldable bottom to form a truck body, and an extensible frame for the bottom for retracting into a position in a body of the vehicle when the door of the trunk compartment is closed.
Another type of load-carrying vehicle is disclosed in U.S. Pat. No. 3,090,514 issued to W. C. Black, Sr., et al. This invention relates to trucks designed to load and unload cargo into or out of planes, and is provided with a retractable bridge mounted on the truck chassis.
U.S. Pat. No. 3,198,571 to B. F. Mojeski discloses a dualpurpose vehicle wherein the vehicle body can be easily converted from a conventional tonneau-type vehicle to a station wagon body or vice versa.
U.S. Pat. No. 3,687,321 to S. E. Goodnart et al discloses a load-carrying vehicle adapted to load and unload cargo and other material into and out of aircraft.
One may further refer to the following U.S. Pat. Nos.: 2,245,417; 4,456,421; 2,890,908; 4,473,855; 3,228,659; 4,616,972; 4,447,042.